Antiplatelets or anticoagulants: No difference in stroke.

Action Points

Treatment of extracranial carotid or vertebral artery dissection with either anticoagulants or antiplatelets shows similar results on death or recurrence of stroke, both of which outcomes are quite rare.

Cervical artery dissection is generally rare, but accounts for 10% to 25% of strokes in young and middle-age patients.

NASHVILLE, Tenn. -- Anticoagulation therapy and antiplatelet treatments were equally effective for preventing recurrent stroke in patients with symptomatic carotid or vertebral artery dissection who participated in a randomized trial comparing the two therapeutic strategies.

During 3 months of follow-up, very few strokes occurred among participants in the Cervical Artery Dissection in Stroke Study (CADISS), suggesting that much larger studies would be needed to fully understand the impact of different treatments in this patient population, neurologist Hugh S. Markus of the University of Cambridge, and colleagues wrote in the journal LancetNeurology, published Feb. 12.

Just 2% of the 250 patients enrolled in the study had recurrent strokes during this observation period, which is a much lower percentage than has been reported by some.

Markus also presented study findings Thursday at the International Stroke Conference, in Nashville, Tenn.

Because recurrences were so rare, a definitive study comparing the efficacy of the two treatment strategies would require a sample size of close to 10,000 patients, Markus told MedPage Today.

"Some people have suggested that the rate of recurrence is very high in these patients -- as high as 15% in the first few weeks," Markus said. "This study tells us that the rate of recurrence is much lower -- closer to 2%. This is very reassuring for patients, and it probably means that it doesn't really matter which treatment you give."

Common Stroke Cause in Younger Adults

Cervical artery dissection begins as a tear in a carotid artery in the neck, which causes blood to pump into arterial walls and split their layers.

The condition is rare, but it is one of the most common cause of strokes in young and middle-age adults , accounting for between 10% and 25% of strokes in this age group, the researchers noted. Studies also suggest that the secondary stroke risk is as high as 20% in these patients, especially if they present local symptoms, such as headache, or with stroke or transient ischemic attack.

"The risk of early recurrence of stroke has led many clinicians to advocate the use of anticoagulation from presentation until 3 to 6 months after dissection," the researchers wrote. "However, others believe that antiplatelet drugs might be sufficient."

Determining if this is the case is important, the researchers noted, because of the known increased hemorrhage risk with anticoagulation therapy.

The CADISS study included 118 carotid and 132 vertebral artery dissection patients treated at specialized stroke or neurology centers in the U.K. and Australia. All patients were enrolled and randomized within 7 days of symptom onset, and the patients were randomly assigned to receive either antiplatelet or anticoagulant drugs for 3 months.

The specific drug regimen was decided by the attending clinician, and the primary endpoint was ipsilateral stroke or death. The mean time to randomization was 3.65 days

Major presenting symptoms included stroke or transient ischemic attack (n=224) and local symptoms (headache, neck pain, or Horner's syndrome n=26). Roughly half of participants received antiplatelet treatment (n=126) and the other half (n=124) received anticoagulant treatment with either warfarin or heparin.

2% of Patients Had Recurrent Strokes

Just four (2%) patients experienced stroke recurrence during follow-up, and all recurrent strokes were ipsilateral. There were three strokes or deaths among the antiplatelet therapy patients (2%), and one such event in the anticoagulant therapy group (odds ratio [OR] 0.335, 95% CI 0.006-4.233; P=0·63).

One major bleeding (subarachnoid hemorrhage) occurred in the anticoagulant group.

Central review of imaging failed to confirm dissection in 52 patients. Pre-planned per-protocol analysis excluding these patients showed stroke or death in three (3%) of 101 patients in the antiplatelet group versus one (1%) of 96 patients in the anticoagulant group (OR 0·346, 95% CI 0·006-4·390; P=0·66).

Potential study limitations cited by the researchers included the inability to centrally confirm diagnosis and dissection and the wide variety of antiplatelet therapies among study participants.

"CADISS was designed as a pragmatic trial and therefore the choice of antiplatelet drugs was at the discretion of the clinician," the researchers wrote. "Prescription of dual antiplatelet treatment for all patients might have improved efficacy."

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